This core will oversee and conduct the morphological analyses for Projects 2, 3 and 4 using light microscopy with specialized stains, transmission and scanning electron microscopy, immunocytochemistry and electron beam probe micro-analysis. Project 2 will supply biopsy samples from the kidney (cortex to papilla) of a selected group of human stone formers while Projects 3 and 4 will use the genetic hypercalciuric stone forming rat (GHS rat) from the colony of Dr. David Bushinsky at the University of Rochester, Rochester, NY.